At a broadcasting station, a magnetic tape, a magneto-optical disc, etc. have been conventionally used to store program data. However, since storing large volume data and rapid accessing became possible by a HDD (Hard Disk Drive) or a semiconductor memory, such as a SSD (Solid State Disk), in recent years, a video server which stores the program data in those storage devices has been introduced.
In the video server, since a plurality of program data are stored in a large amount of storage device unlike the magnetic tape, file management of program data is required. Even if the large capacity storage device is used, it is important to erase a file of the unnecessary program data promptly to reserve recordable capacity greatly so that the video server can record new program data at any time.
In order to manage recordable capacity, it is proposed a technique which discovers and erases the oldest file recorded on a storage device when a program data file is recorded to exceed a predetermined capacity (for example, JP, PH08-115333A).
However, in the conventional video server, even when performing multitask operation, priority is given to recording and playing. Since erasing is processed with the lowest priority and the files are erased one by one, there is a problem that erasing is not performed promptly.